Stein said that Baraka, the founding executive director of the U.S. Human Rights Network who has served on boards of several international human rights organizations, is an "activist, writer, intellectual and organizer with a powerful voice, vision, and lifelong commitment to building true political revolution," the Washington Examiner reports.

Stein received just under 0.4 percent of the national vote when she ran for president on the Green Party ticket in 2012.

The latest polls after the Republican and Democratic National Conventions has Stein receiving 5 percent of the vote, as the public seeks alternatives to Hillary Clinton and Donald Trump, who both have historically high negative ratings, CNN reports.

Although she is not expected to mount any sort of serious challenge, the support she and Libertarian Party nominee Gary Johnson, who is polling at 9 percent, receive could be crucial in determining which of the major candidates wins swing states.

Stein was in Philadelphia during the Democratic National Convention in an effort to persuade disappointed Bernie Sanders supporters to reject Clinton and switch over to the Green Party, Philly.com reported.